Capacitor for a semiconductor

Abstract

An improved capacitor for a semiconductor memory, and method for depositing material on a substrate is shown. The material to be deposited is energized by irradiation with light in a chamber in which a CVD method is carried out. The energy induced by the irradiation remains in the molecules of the material even after the molecules have lain on the substrate. With the residual energy, the molecules can wander on the substrate even to a hidden surface. Due to this wandering, the deposition can be performed also on the inside of a deep cave.

What is claimed is: 
     
       1. A capacitor formed in a substrate comprising: a trench formed within a semiconductor substrate and having an opening at a surface of said substrate;   an insulating film provided on the inside surface of said trench; and   a capacitor extending in said trench,   wherein said insulating film intervenes between said inside surface and said capacitor and said trench has an area, when measured with respect to a plane parallel to the surface of said substrate in its inner position, greater than the area of siad opening.   
     
     
       2. The capacitor of claim 1 wherein said capacitor comprises a pair of electrode layers and a dielectric layer disposed between said pair of electrode layers. 
     
     
       3. The capacitor of claim 2 wherein each of said electrode layers comprises a conducting material. 
     
     
       4. The capacitor of claim 2 wherein each of said electrode layers comprises a semiconductor material. 
     
     
       5. The capacitor of claim 2 wherein said electrode layers are a layer comprising a conducting material and a layer comprising a semiconductor material. 
     
     
       6. The capacitor of claim 2 wherein said dielectric layer comprises a material selected from the group consisting of silicon oxide and silicon nitride. 
     
     
       7. The capacitor of claim 1 wherein said trench laterally extends at its bottom. 
     
     
       8. A capacitor formed in a substrate comprising: a trench formed within a semiconductor substrate;   an insulating film provided on the inside surface of said trench; and   a capacitor extending in said trench,   wherein said insulating film intervenes between said inside surface and said capacitor.   
     
     
       9. The capacitor of claim 8 wherein said capacitor further extends outside said trench. 
     
     
       10. The capacitor of claim 8 wherein said capacitor comprises a pair of electrode layers and a dielectric layer disposed between siad pair of electrode layers. 
     
     
       11. The capacitor of claim 10 wherein each of said electrode layers comprises a conducting material. 
     
     
       12. The capacitor of claim 10 wherein each of said electrode layers comprises a semiconductor material. 
     
     
       13. The capacitor of claim 10 wherein said electrode layers are a layer comprising a conducting material and a layer comprising a semiconductor material. 
     
     
       14. The capacitor of claim 10 wherein each of said electrode layers comprises silicon. 
     
     
       15. The capacitor of claim 10 wherein each of said electrode layers comprises titanium silicide. 
     
     
       16. The capacitor of claim 10 wherein said electrode layers are a layer comprising silicon and a layer comprising titanium silicide. 
     
     
       17. The capacitor of claim 8 wherein said insulating film comprises silicon oxide. 
     
     
       18. The capacitor of claim 10 wherein at least one of said electrode layers is doped with phosphorus. 
     
     
       19. The capacitor of claim 10 wherein at least one of said electrode layers is a polysilicon layer. 
     
     
       20. The capacitor of claim 10 wherein said dielectric layer comprises a material selected from the group consisting of silicon oxide and silicon nitride.